Mastic gun



FIG. 1 is a back perspective view of a mastic gun.

FIG. 2 is a front perspective view of a mastic gun.

FIG. 3 is a top view of a mastic gun.

FIG. 4 is a right side view of a mastic gun.

FIG. 5 is a front view of a mastic gun.

FIG. 6 is a back view of a mastic gun; and,

FIG. 7 is a bottom view of a mastic gun.

The broken lines are included for the purpose of illustrating environmental structure and form no part of the claimed design. 

The ornamental design for a mastic gun, as shown and described. 